1. Field of the Invention
The present invention relates generally to a locking device for an internal battery pack cover of a mobile phone, and in particular, to a locking device for an internal battery pack cover of a mobile phone, which can easily detach the cover from a main body of the mobile phone by a sliding movement of a button unit provided on the cover and the resulting rotation of lockers.
2. Description of the Related Art
Generally, a mobile phone includes an internal battery pack 10 (as shown in FIG. 1) as a power supply source. The internal battery pack 10 is mounted and electrically connected to the rear side of a main body 1 and covered by a cover 40, which is detachably mounted onto the rear side of the main body 1 by a locking means 20 provided on the rear side of the main body 1.
A conventional method of mounting the cover 40 of the internal battery pack 10 is to slidingly mount the cover 40 along a guide rib provided on the rear side of the main body 1. Another conventional method of mounting the cover 40 of the internal battery pack 10 is to mount the cover 40 onto the rear side of the main body 1 by locking hooks formed at the lower end of the cover 40 into slots formed on the main body 1 and pressing down a locking means formed on the top end of the cover 40.
FIG. 1 illustrates a conventional locking device for an internal battery pack cover of a mobile phone. The conventional locking device electrically connects the battery pack 10 to the rear side of the main body 1 which includes a lower case frame 1a. 
The lower case frame 1a has a battery-receiving compartment 1b on the rear side thereof. A connection terminal (not shown) is protrudingly provided at the lower end of the compartment 1b. Also, a mount section 1c is provided at the upper end of the compartment 1b. A locking means 20 for locking the cover 40 of the battery pack 10 is formed on the mount section 1c. 
Referring to FIG. 2, the cover 40 of the internal battery pack 10 includes a pair of hooks 42 formed at the lower end thereof and a lock groove 41 formed at the upper end thereof. The cover 40 can be secured to the rear side of the main body 1 by inserting the hooks 42 into hook slots 1d formed on the main body 1 and then pressing down the cover 40 to engage the locking means 20 into the lock groove 41.
FIG. 3 is a cross-sectional view of a conventional locking device for an internal battery pack cover of a mobile phone. In order to detach the cover 40 of the internal battery pack 10 from the main body 1, the locking means 20 should be pulled backwardly. A pair of locks 21 formed on the lower end of the locking means 20 are also pulled backwardly and withdrawn from the lock groove 41 of the cover 40. Thus, the cover 40 can be separated from the main body 1.
The mount section 1c has a moving space sufficient to allow a sliding movement of the locks 21 in a horizontal direction.
As illustrated in FIG. 3, at least one guide rib 23 is formed on the lower case frame 1a of the main body 1.
The guide rib 23 has a hook portion 23a at the upper end thereof. The hook portion 23a is hooked on a stopper 2 formed on the lower case frame 1a, which prevents the locks 21 from being released out during the sliding movement in a horizontal direction. A spring 30 is mounted in the mount section 1c, as an elastic means for generating an elastic force against the locks 21. While one end of the spring 30 is supported by the lower case frame 1a, the other end presses the locks 21.
As described above, the conventional locking device provides a sufficient space to allow the locks to be slidingly movable within the mount section in a horizontal direction, which may increase the size of the mobile phone and deteriorate the appearance of the mobile phone.
Once the hooks formed at the lower end of the cover are secured into the hook slots formed on the main body of the mobile phone, they will not be smoothly taken out from the hook slots, thereby making it difficult to remove the cover from the main body.
In addition, the conventional locking device has a complicated structure due to the space provided for a sliding movement of the locks.